Kibana version: master

Elasticsearch version: master

Server OS version: macOS

Browser version: chrome

Browser OS version: macOS

Original install method (e.g. download page, yum, from source, etc.): source

Describe the bug:
Unable to create canvas element that uses elasticsearch data source. Getting error "Unauthorized"

Steps to reproduce:

1. Install sample data set
2. Create new canvas workpad
3. Add an element that pulls documents from the sample data index.
4. Notice the warning message

Expected behavior:

Screenshots (if relevant):

Errors in browser console (if relevant):

Provide logs and/or server output (if relevant):

Any additional context:

cc @elastic/kibana-canvas